The present invention relates and particularly to an improved cap for a fuel tank for use in a motor vehicle.
Generally, in a fuel tank of the gravity-feed type, in a two-wheeled motor vehicle and the like, there has been employed a fuel tank cap having a path formed in the fuel tank cap body for communicating the tank interior with the atmosphere so as to prevent an undesirable occurrence such as an impedance to the smooth feeding of the fuel due to a reduction of pressure in the fuel tank as the fuel is consumed.
The known fuel tank cap of the above described type, however, has the disadvantage that fuel contained in the fuel tank may leak to the atmosphere when the vehicle is inclined or tilted to a large degree, for example, by accidental overturn, etc.
In order to eliminate the aforementioned disadvantage, the present invention utilizes a conventional fuel tank cap in which a sensor valve unit is incorporated in the path communicating the tank interior with the atmosphere. The above arrangement, however, still has the disadvantage that, in addition to the fact that the sensor valve is incapable of absolutely closing the path, a valve body accommodated in a valve housing is undesirably often times lifted, thereby seating the valve, by an abnormally high internal pressure of the fuel tank caused by evaporation of the fuel within the fuel tank due to external heat or the like, and thus the path is blocked, which results in a further raising of the pressure within the fuel tank, resulting in even greater danger.